Multi-objective optimization of supercritical carbon dioxide recompression Brayton cycle considering printed circuit recuperator design

Abstract

Supercritical carbon dioxide recompression Brayton cycle is well suited to a broad range of applications including nuclear and concentrated solar energy. As printed circuit recuperators are employed to optimize the thermal performance of the cycle, the recuperator optimal design is required with the objective of maximizing the cycle thermal efficiency and minimizing the total cycle cost. In this paper, a thermo-economic model of recompression Brayton cycle with the S-shaped fin printed circuit recuperator is developed to perform multi-objective optimization considering the recuperator design parameters (i.e. mass fluxes and enthalpy efficiencies of recuperators and recompression fraction). Nondominated sorting genetic algorithm is used to obtain Pareto frontier. The results show that compared to the mass fluxes, the enthalpy efficiencies of recuperators and recompression fraction play more important roles in the optimization. From the Pareto frontier, the optimum range of the cycle thermal efficiency is 0.4303–0.5380 and that of the total cycle cost is 7.468 M$–12.31 M$. As high cycle thermal efficiency is preferred, the high recompression fraction, high mass flux and high enthalpy efficiency of low temperature recuperator, low mass flux and high enthalpy efficiency of high temperature recuperator are required. In contrast, as low cycle cost is preferred, the opposite selections of design parameters are required.